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    <title>Document</title>
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    <script>
        let arr1={name:'张三',a:1}
        let arr2={name2:'李四',b:2}
        let arr3 = Object.assign({},arr1,arr2)
        let arr4 = {...arr1,...arr2}
        
        console.log(-0 === +0) //   true
        console.log(Object.is(-0,+0))  // false
        Object.is('foo', 'foo');     // true
        Object.is(window, window);   // true
        
        Object.is('foo', 'bar');     // false
        Object.is([], []);           // false
        
        var foo = { a: 1 };
        var bar = { a: 1 };
        Object.is(foo, foo);         // true
        Object.is(foo, bar);         // false
        
        Object.is(null, null);       // true
        
        // 特例
        Object.is(0, -0);            // false
        Object.is(+0, -0);           // false
        Object.is(0, +0);            // true
        Object.is(-0, -0);           // true
        Object.is(NaN, 0/0);         // true
        NaN == NaN                   // false
    </script>
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